Figure 1
From: Pulsed Sagnac source of polarization-entangled photon pairs in telecommunication band
Generation of correlated photon pairs in PPLN crystal. (a) Correlated photon pairs in the telecommunication band are generated via non-collinear QPM-SPDC in a 10-mm-long type-0 PPLN crystal. The two photons are spatially well separated from the pump beam direction with a full-opening angle of 4.6°, and then coupled by single-mode fibres through the coupling optics. (b) Single and (c) coincidence counting rates as functions of pump power. Inset in c shows the coincidence-to-accidental-ratio (CAR) as a function of the pump power.
